'Check safeguard' message on dash

[jiffy1986]

Hi, my 54 plate vectra sri cdti has the check safeguard message on every startup. It has done this since i have owned the car. I have read the codes with my snap-on solus. It came up with B2955 - antitheft warning system sensor datalink/horn connection. Tried to erase but comes straight back, any ideas???

[AntB]

If you set your alarm off does a siren in the boot sound or is it the horn(s) under the bonnet? The reason I ask is that a few people, myself included, unplug the siren in the boot which then forces the system to use the twin horns as they are much louder, but it does mean it throws up the "Check Safeguard" message every time the ignition is turned on.

[jiffy1986]

I will check later when i get home and post my findings, thanks

[sscully]

Check your interior light sensor. One of the little sensors on mine was faulty.

[jiffy1986]

Right, just locked the car with me in it, waited for the led in the alarm button to stop flashing fast, then moved around in the car and it never went off, so i opened the door and it went off, it was the siren in the boot that sounded and not the horn. Does the alarm have a control unit? Or is it integral with the siren?

[AntB]

As sscully said, there's a chance either/both the two ultrasonic sensors are faulty, the wiring loom/plug is somehow dislodged or even the button on the dash to disable the ultrasonics is at fault.

[john506]

Where about is the siren in the boot? cheers

[AntB]

It's on the left hand side, in the cubby-hole, forward of the fuses.

[jiffy1986]

I have pulled the ultrasonic sensors down out of the roof, the wiring goes up in to the roof and i cant find a plug where it joins the roof loom. There is a trade in vectra sri in work so i might swap the sensors over to try. Is there a control unit for the alarm also?

[Bluzel]

Have this exact same problem. Alarm sounds when open all doors and bonnet. And rear demisters are fine (not estate) ultrasonics disabled ok when button pressed. Took ultrasonic module out and disconnected the ribbon cable. Still cant see anything wrong...altho i didnt check voltage etc as I dunno how